Upper extremity Flashcards
Elbow Flexors (5)
Biceps brachii Brachialis (lateral side of biceps) Brachioradialis Pronator teres Extensor carpi radialis longus
“3 Boys in PE”
Supination of Forearm (4)
Supinator
Extensor carpi radialis longus
Biceps brachii
Brachioradialis
“SEBB”
Wrist extensors (7)
Extensor carpi ulnaris Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor indicis Extensor pollicis longus
- All dorsal forearm muscles, 7E’s
- Note: the top 3 can be gone and you still preserve wrist extension
Wrist flexors (7)
Flexor carpi radialis Flexor carpi ulnaris Flexor digitorum superficialis Flexor digitorum profundus Flexor pollicis longus Abductor pollicis longus Palmer's longus
“5 F’s And Palm”
- All median nerve innervated except for…
- FCU and the ulnar half of FDP (ulnar n.)
- Abductor pollicis longus (radial n.)
Elbow Extensors
Triceps
Anconeus
Elbow Pronators
Pronator teres Pronator quadratus Palmaris longus Bradioradialis Flexor carpis radialis
APB (intrinsic thumb muscle) vs APL (extrinsic thumb muscle)
APB- ABduction from the palm (all the AFO muscles are median nerve innervated
APL- ABduction from the midline (“all peanut lovers”); affected in de quervain’s tendonitis)
Intrinsic muscles of the hand in their relative palmar anatomical position from lateral to medial
All For One And One For All: A: abductor pollicis brevis (APB) F: flexor pollicis brevis (FPB) O: opponent pollicis (under APB and FPB) A: adductor pollicis O: opponens digiti minimi F: flexor digiti minimi A: abductor digiti minimi
*Note: FPB may have ulnar and/or median innervation
Brachial plexus injury after median sternotomy
The medial cord is most vulnerable!
How to distinguish medial cord injury vs. ulnar neuropathy
Check the medial cutaneous nerve which comes off of the ulnar nerve–>
If the problem is medial cord, the medial cutaneous will be affected.
If the problem is the ulnar nerve, the medial cutaneous will be spared.
*Confirm this!
What nerve is vulnerable during axillary node dissection?
ICBN- intercostal brachial nerve
Clinically will have decreased sensation on the medial part of the upper arm
Thoracic outlet syndromes
- Interscalene
- Costoclavicular
- Pectoralis minor (coracoid process)
Axillary Nerve
Anterior division:
- anterior deltoid
- middle deltoid
Posterior Branch:
- teres minor
- posterior deltoid
- sensory lateral shoulder
*Need to always examine: all 3 heads of the deltoid, teres major, and teres minor
Anterior interosseous branch of the median nerve supplies…
Flexor pollicis longus and pronator
Arcade of Struthers can be a site of entrapment of what nerve?
Ulnar nerve
What muscles are related to the Froment’s sign?
FPL and adductor pollicis
Froment’s sign is positive in which palsy?
Ulnar nerve palsy
Which muscle is not affected in PIN syndrome?
Extensor carpi radialis longus (ECRL)
*Radial nerve innervated before the radial nerve travels through the supinator to become the PIN)
Long head of the biceps
Insertion: on the glenoid
*intracapsular but extrasynovial–> therefore, not effected by diseases that affect synovial fluid
Triceps
Lateral head (more c7?) Long head (more c8?) Medial head (more c8?)
Contraction of the triceps muscle can result in a mononeuropathy of what nerve?
Radial nerve– courses through the triceps in close proximity to the medial and lateral heads.
Common sites of Radial Nerve Compression Neuropathies
Axilla- crutch palsy
Arm- spiral groove (saturday night palsy), walker palsy (triceps)
Forearm- posterior interosseous syndrome, extrinsic compression (tumors, vascular lesions, etc.)
Wrist- superficial radial sensory branch (“cheiralgia paresthestica”), handcuff/wrist watch palsy
Arcade of Frohse
Where the radial nerve passes through the supinator muscle and becomes the PIN.
Anconeus
It’s innervation comes off the radial nerve before the spiral groove.
C8 muscle
Radial Nerve Muscular Branches
Triceps brachii (3 heads) Ancones -------------------spiral groove Brachioradialis ECRL (directly next to brachioradialis) Supinator -------------------thru supinator (Arcade of Frohse) so now PIN ECRB? EDC EDM ECU APL EPB EPL EIP
4 anatomical areas for problems with the median nerve in so called “pronator syndrome”
- Ligament of Struthers (present in <1% of ppl)
- Lacertus fibrosis (fascial band off the biceps)
- Pronator teres
- Sublimes arch
AIN
- Largest motor branch of the median nerve
- Runs on the anterior side of the forearm
- Innervates 3 muscles: FPL, FDP (1/2), and PQ
- pure motor nerve: contains no cutaneous fibers, but still carries pain fibers
*Always think of neuralgic amyotrophy–> AIN + serratus anterior–> self-limited
AIN Syndrome
- Acute onset of weakness of the thumb and index finger
- Usually no sensory complaints
- Clinical test: can’t make a circle with the thumb and index finger due to hyperextension of the PIP of the thumb
4 sites of ulnar nerve entrapment
Arcade of Struthers (70% of ppl have this)
Retrocondylar groove/medial epicondylar groove
Cubital tunnel (as it passes through the two heads of the FCU)
Guyon Canal
Flexor carpi ulnaris
- Innervated by the ulnar nerve
- Makes up the floor of the cubital tunnel
Flexor digitorum profundus
-ulnar part is innervated by a branch of the ulnar nerve that branches off after going through the cubital tunnel
Medial collateral ligament of the elbow
-Same as ulnar collateral ligament
3 Components:
- anterior oblique
- posterior oblique ligament (forms the floor of the cubital tunnel)
- small transverse ligament
*Note UCL reconstruction= Tommy John Surgery
What forms the Guyon canal?
Medial: pisiform
Lateral: hook of the hamate
Floor: proximally traverse carpal ligament, distally pisohamate ligament
*Site for Ulnar nerve entrapment
Froment’s sign= ulnar neuropathy
Weak adductor polices (ulnar) strong FPL (median)
To perform the test, a patient is asked to hold an object, usually a piece of paper, between their thumb and index finger.
Coronoid process of ulna
Insertion of the brachialis muscle
Origin of the:
- FDS
- FDP
- Pronator teres
- +/- FPL
Coracoid process of the scapular
Coracobrachialis
Pec Minor
Short head of the biceps brachii
Chief function of the lumbricals
extension of the IP joints; secondary function is flexion of the MCP
True claw-hand deformity is caused by injury to what nerves?
Median and ulnar nerves
Stretching the intrinsic muscles of the fingers is best accomplished by…
hyperextending the MP joints and flexing the IP joints
What are the functions of the flexor digitorum superficialis?
- flexion at the PIP
- flexion at the MCP
- adduction of the digits (don’t forget!!!)
What carpal bone in the proximal row receives muscular attachment?
pisiform
DeQuervain’s is tenosynovitis of what muscles?
- APL
- EPB
“Extensor hood” is an extension of what tendon?
extensor digitorum longus tendon
Spontaneous rupture of what tendon can be seen in RA?
extensor pollicis longus
Complete lesions of both the median and ulnar nerves at the elbow will not abolish wrist flexion since this movement can still be performed by…?
Abductor pollicis longus (radial innervation)
The flexors of the wrist joint are innervated by…?
Ulnar, median, and radial nerves
Aberrant lumbricals can be a cause of…?
Carpal tunnel syndrome
What lies deep to the flexor retinaculum (transverse carpal ligament)?
Median nerve
*Note: no arteries in the carpal tunnel
What then does not go through the carpal tunnel?
FCR
Weakness of the interosseous muscles?
Both sets (dorsal and palmar) are innervated by the deep branch of the ulnar nerve.
AFO of the thenar and hypothenar
- APB: important for pulp to pulp prehension
- FPB: deep (ulnar n.) vs. superficial head (median n.)
- Opponens
Adductor pollicis
- If weak, will see FPL substitute in Froment’s sign
- Note that there is both a transverse and oblique head
- In testing, make sure the thumb is not flexed
Riche-Canniez Anastomosis
- anomalous communication within the hand between motor branch of median nerve and deep branch of ulnar nerve
- importance: abnormalities in first dorsal may reflect median nerve problem, not ulnar (32% have FPB entirely ulnar innervated, 33% have FPB entirely median innervated)
Hand intrinsic muscles
- thenar
- hypothenar
- adductor pollicis
- dorsal interosseous
*Note: if you have an intrinsic minus hand, you don’t have nay of the above.
Palmar interosseous
- adduction of digits
- assist MCP flex of index, ringer, and little finger
- assist ext IP of index, ring, and little finger
*Note: the long finger has no palmer interosseous attached
Dorsal interosseous
- abduction of digits
- assist MCP flexion
- assist ext IP
Lumbricals
- originate from the tendons of the FDP
- chief function is extension of the IP joints (reinforcing action of the EDC and interosseous)
- secondary function can be MCP flexion if IPs extended
*Note: each lumbrical has same innervation as corresponding FDP (median and ulnar innervation); lumbricals really playing a coordinating role between flexor and extensor systems
Finger extension
- EDC goes to the fingers
- Index and little finger both have an extra extensor
- Middle and ring finger only have the EDC–> can’t extend the ring finger when the middle finger is flexed
*Note: to test the extensor indices proprius it is important to completely flex the MCP of long and ring fingers to eliminate action of EDC
Adductor pollicis
- If weak, will see FPL substitute in Froment’s sign (seen in ulnar nerve problems)
- Careful when exploring the first dorsal interosseous to not go too deep otherwise you’ll be in the adductor policies
- both a transverse and oblique head
- in testing, be careful that the thumb is not flexed (to eliminate FPL action) and that the wrist is extended (to relax EPL).
Compartments at the wrist
- APL, EPB
- ECRL, ECRB
* lister’s tubercle - EPL
- Ext digitorum and Ext indicis
- EDQ (ext. digiti minimi)
- ECU
